title: A high-fat meal promotes lipid-load and apolipoprotein B-48 receptor transcriptional activity in circulating monocytes.
abstract: BACKGROUND
  The postprandial metabolism of dietary fats results in the production of apolipoprotein B-48 (apoB48)-containing triglyceride-rich lipoproteins (TRLs), which cause rapid receptor-mediated macrophage lipid engorgement via the apoB48 cell surface receptor (apoB48R). Monocytes circulate together with apoB48-containing TRLs in the postprandial bloodstream and may start accumulating lipids even before their migration to tissues and differentiation to macrophages.
  
  
  OBJECTIVE
  We sought to determine whether circulating monocytes are equipped with apoB48R and whether, in the postprandial state, circulating monocytes accumulate lipids and modulate apoB48R transcriptional activity after intake of a high-fat meal.
  
  
  METHODS
  In a crossover design, we studied the effect of a high-fat meal on fasting and postprandial concentrations of triglycerides, free fatty acids, cholesterol, and insulin in 12 healthy men. TRLs and monocytes were freshly isolated at fasting, hourly until the postprandial peak, and at the late postprandial phase. TRLs were subjected to triglycerides, apoB48, and apolipoprotein B-100 analyses; and lipid accumulation and apoB48R mRNA expression levels were measured in monocytes.
  
  
  RESULTS
  Monocytes showed a time-dependent lipid accumulation in response to the high-fat meal, which was paralleled by an increase in apoB48R mRNA expression levels. These effects were coincident only with an increase in apoB48-containing TRLs in the postprandial phase and were also observed ex vivo in freshly isolated monocytes incubated with apoB48-containing TRLs.
  
  
  CONCLUSIONS
  In a setting of abundant plasma apoB48-containing TRLs, these findings highlight the role of dietary fat in inducing lipid accumulation and apoB48R gene transcription in circulating monocytes.
authors.affiliation: Laboratory of Cellular and Molecular Nutrition, Instituto de la Grasa, Seville, Spain.
authors.forename: Lourdes M
authors.initials: LM
authors.lastname: Varela
authors.forename: Almudena
authors.initials: A
authors.lastname: Ortega
authors.forename: Beatriz
authors.initials: B
authors.lastname: Bermudez
authors.forename: Sergio
authors.initials: S
authors.lastname: Lopez
authors.forename: Yolanda M
authors.initials: YM
authors.lastname: Pacheco
authors.forename: Jose
authors.initials: J
authors.lastname: Villar
authors.forename: Rocio
authors.initials: R
authors.lastname: Abia
authors.forename: Francisco J G
authors.initials: FJ
authors.lastname: Muriana
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D004041:Dietary Fats / Q000009:adverse effects*; D006801:Humans; D015228:Hypertriglyceridemia / Q000378:metabolism; D007700:Kinetics; D050356:Lipid Metabolism; D008055:Lipids / Q000097:blood*; D008297:Male; D009000:Monocytes / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D018110:Receptors, Lipoprotein / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016037:Single-Blind Method; D015533:Transcriptional Activation; D055815:Young Adult
chemical_list: D004041:Dietary Fats; D008055:Lipids; D012333:RNA, Messenger; D018110:Receptors, Lipoprotein; C411291:apo B48 receptor